Motorists are advised to avoid the area and expect delays.
The New Zealand Transport Agency Waka Kotahi said the detour for southbound traffic was via the Te Wharepu Rd off-ramp, turning right on Glen Murray Rd, continuing on Te Ohaki Rd, then Harris St, before turning left on Tainui Bridge Rd, right on Great South Rd, continuing on Gordonton Rd and joining back on SH1.
A Fire and Emergency New Zealand spokesperson said it received a call to the incident at 7.11am and responded with three crews, one from Te Kauwhata and two from Huntly.
“We just assisted police and ambulance. No one was trapped.”
St John Ambulance has been approached for comment.